This seamless clamp on gear ring clamps securely around the focus barrel of your lens by tightening one little screw (allen key is included). Once tightened, the slit in the ring disappears and makes the ring seamless. The tooth size is M0,8.
Professional 15mm LW single-sided follow focus with 1:1 gear ratio. Compact, adjustable design includes .8 mod and friction gears for cine and DSLR lenses.